He's right. It doesn't really end and endings are one of, if not the crucial element of a film that the audience uses to judge whether or not they liked it. It's the last impression of the film you'll get and I understand Whedon's qualms with it as a filmmaker. I'm glad he's making a conscious effort to not have that happen in Avengers 2. One of my problems with the Marvel movies is that they are trying to fit together like a puzzle while sacrificing the films' rights and ability to stand on their own and not as parts of a conjunction.

On behalf of The Empire Strikes Back, its ending gets a pass from me because what happens before it is so great.